Updated USB Specifications

Last week was spent updating the VIUD specifications on the new store site which includes a number of values related to the USB (read on for an explanation of each benchmark):

	16 GB	32 GB	64 GB	128 GB	256 GB
Usable Capacity	15,961,546,752 bytes	31,651,479,552 bytes	62,911,414,272 bytes	125,818,503,168 bytes	253,121,003,520 bytes
File System	FAT32	FAT32	exFAT	exFAT	exFAT
HD Tune Pro Benchmarks
Read	106.5 - 116.7 MB/s	114.2 - 127.9 MB/s	119.9 - 130.7 MB/s	181.2 - 193.3 MB/s	56.0 - 146.8 MB/s
Average Read	111.7 MB/s	121.9 MB/s	123.5 MB/s	187.7 MB/s	142.1 MB/s
Access Time	0.889 ms	0.973 ms	1.16 ms	0.747 ms	0.811 ms
Crystal Disk Mark Benchmarks
Read Seq Thread	121.6 MB/s	130.1 MB/s	133.3 MB/s	208.8 MB/s	149.2 MB/s
Read Rnd Thread	16.4 MB/s	14.3 MB/s	14.1 MB/s	6.03 MB/s	22.1 MB/s
Read Seq	119.8 MB/s	127.6 MB/s	131.6 MB/s	205.4 MB/s	146.6 MB/s
Read Rnd	15.0 MB/s	13.3 MB/s	13.6 MB/s	5.47 MB/s	19.2 MB/s
Write Seq Thread	24.2 MB/s	34.8 MB/s	38.2 MB/s	132.5 MB/s	94.1 MB/s
Write Rnd Thread	0.051 MB/s	0.097 MB/s	0.69 MB/s	0.224 MB/s	1.37 MB/s
Write Seq	22.4 MB/s	25.6 MB/s	17.8 MB/s	129.8 MB/s	22.6 MB/s
Write Rnd	0.054 MB/s	0.055 MB/s	0.81 MB/s	0.0048 MB/s	1.07 MB/s
USBFlashBench Benchmarks
Read	116.70 MB/s	124.93 MB/s	127.54 MB/s	206.48 MB/s	131.13 MB/s
Write	22.72 MB/s	29.40 MB/s	32.89 MB/s	133.83 MB/s	55.93 MB/s
Link	157023	157008	157022	157018	157011
4GB File Copy
Copy	2:38.3 (24.1 MB/s)	1:49.5 (34.8 MB/s)	1:42.1 (37.3 MB/s)	0:30.2 (126.3 MB/s)	0:44.8 (85.2 MB/s)
Read	0:33.4 (114.1 MB/s)	0:31.2 (122.1 MB/s)	0:30.6 (124.6 MB/s)	0:18.4 (206.9 MB/s)	0:28.8 (132.7 MB/s)

The VIUD's usable capacity is slightly less than the stated capacity which is typical of just about any mass storage device. Part of the overall device's drive space is taken up by the file allocation table which takes more space on larger drives. The other part, however, is just due to the USB board manufacturer using a slightly smaller size than stated. Perhaps this is due to a technical reason or, more likely, an economic one.

HD Tune Pro is a basic disk benchmarking and testing application. Unfortunately the write tests don't seem to work on newer operating systems but the read and error tests do give a nice visual display. I'd like to point out the low minimum read speed for the 256 GB VIUD which can be easily seen in the following graph:

VIUD 256 GB HDTunePro Read Benchmark

All other VIUD capacities have a roughly flat graph for the blue line but the 256 GB model has much slower read speeds at exactly 32 GB intervals for whatever reason.

CrystalDiskMark is another basic drive benchmarking tool that outputs several read and write tests:

• Seq Thread = Sequential read/write, 128 KB block size with multiple queues and threads
• Rnd Thread = Random read/write, 4 KB block size with multiple queues and threads
• Seq = Sequential read/write, 1 MB block size with single thread
• Rnd = Random read/write, 4KB block size with single thread

USBFlashBench is a simple tool that tests multiple block read/write sizes and then uploads the results to a website and creates nice graphs like:

USBFlashBench Results for the 256 GB VIUD

Finally, the 4GB file copy test is simply the time it takes to copy a 4 GB (4,000,000,000 bytes) file composed of random content to the VIUD and the time it takes to read it back. Due to caching we have to make sure to unplug the VIUD after the write test and then plug it back in to do the read test.

Looking at the Competition

Looking at existing products in the rugged, waterproof or otherwise indestructible USB drive market is useful for a few reasons:

1. It may be that our "best" VIUD already exists.
2. Compare and possible change our design with what is available.
3. Get a better idea of prices if we wish to market our drive.

The following are a selection of better products found from searches of rugged, waterproof or indestructible USB drives.

Corsair Survivor

The Corsair Survivor looks like a relatively nice consumer level rugged and waterproof USB drive. It has a nice waterproof rating of 300 psi and its Aluminum case looks like it would take a pretty good beating. The design, in my opinion, is not ideal with a very large cap which may be easily lost. It has a relatively low price range of $30-85.

LaCie XtremKey  

The LaCie XtremKey looks like a decent candidate for a VIUD with a 300 psi waterproof and to a 10 ton pressure resistant rating. The "resistant" qualifier is suspect but with an all metal case it looks like it could handle being run over by a large car depending on the exact type of metal used (they mention a Zamac alloy but not which one). It has a large cap design like the Survivor which I dislike. Its price point is slightly higher at $85-140 but is not unreasonable for such a rugged device.

One notable specification for this drive is its large range of temperatures, particularly its high temperature limit of 200 °C. Although they again say "resistant" this is much higher than any other USB drive I've seen that actually has any temperature ratings (most don't).

Imation Ironkey Basic

The Ironkey Basic from Imation is a very nice looking drive with what looks like a basic metal case which would protect it from everyday bumps and drops but probably not larger accidents. It is rated waterproof under specification MIL-STD-810 which, as far as I can tell, is close to IP67/68 or essentially just waterproof from basic immersion and not pressure rated.

The drive's price is significantly higher than other rugged drives at $90-300 despite being less rugged. This is likely due to the Ironkey's main purpose of being an encrypted drive. Overall a great looking drive but not exactly what we're looking for our own VIUD. In theory if we wanted encryption it could be done at the software level.

Tyukalov USB Drive

The Tyukalov drive is a unique, one of a kind, custom USB drive which is interesting to compare to the consumer type drives previously found. It was made in a limited quantity of 100 at a relatively high price of $200-250 each but managed to sell out in a short period of 3 weeks. Its unique dual cavity design is not particularly convenient but it boosts the highest waterproof rating of 2000 psi of any USB drive I've seen and undoubtedly an equally high rugged rating.

Eternal Case

The Eternal Case is a product that wasn't out when I initially researched and came up with my VIUD design in the fall of 2012 but is remarkably similar. It just goes to show that if you think of a good idea there's a good chance someone else already has or soon will.

There are no explicit ratings for this custom product but from its design I would guess it should be waterproof to at least 300 psi and would easily withstand being run over by a car. Its price is amazingly low at only $40-75, even for a 32GB Titanium model. Based on what I've researched for prices I'm unsure how they can make a profit at this price. The only negative thing I can see is that the design/manufacture is relatively rough looking.

Wrapping Up...

There are other drives that are marketed as "rugged" but the majority don't actually have an explicit mechanical or waterproof specification. Most appear to be just cheap drives surrounded by a thin metal case with a "rugged" label which is not what I'm looking for my own VIUD. 

Even with this relatively small collection of existing true rugged drives it gives us a relatively good baseline on what is currently available and at what price. It also helps narrow down some of our design constraints, or at least what we would like them to be:

• >2000 psi waterproof rating
• >10 ton crush rating
• >200°C for 3 minutes temperature rating
• $40-300 (depends on capacity, quality, and ultimate rating)

Time will tell whether any of these are actually possible or not....